USA gymnast Simone Biles won Olympic bronze but withdrew from earlier events due to ‘The twisties’ and resulting mental health issues. Family Doctor Graham Easton looks at the evidence for what causes this condition.

Childhood myopia: A new study finds an increase in childhood short-sightedness during the pandemic. Lead author Jason C. S. Yam explains the potential impact of lockdowns on eye health by increasing close work on screens and decreasing outside activity.

Cannabis and vomiting: Alison van Diggelen reports on an under recognised condition, Cannabinoid Hyperemesis Syndrome [CHS] where users of marijuana get bouts of vomiting, nausea, and severe abdominal pain that can need hospitalisation. It mostly impacts long term users though some younger people who smoke concentrates only a few times a week have had it too. Severe weight loss and the dehydration caused by vomiting can have long term impacts on the heart, liver and kidneys even causing death in extreme cases.

Oxygen monitoring: Updated guidance showing that pulse oximeters – a device designed to measure early signs of a dangerous drop in oxygen - works less well in people with darker skin.

Presenter: Claudia Hammond

(Picture: Simone Biles of Team United States competes in the Women's Balance Beam Final on day eleven of the Tokyo 2020 Olympic Games at Ariake Gymnastics Centre in Tokyo, Japan. Photo credit: Jamie Squire/Getty Images.)